Chain length-dependent fate and phytotoxicity of PFAS in plants.

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that accumulate in plants, posing risks to terrestrial food webs. This review provides a mechanistic synthesis of the behavior of PFAS in plants, from root uptake to subcellular responses. Short-chain PFAS preferentially translocate acropetally via apoplastic and symplastic pathways, bypassing the Casparian strip, whereas long-chain congeners are largely retained in roots due to adsorption to cell wall polysaccharides (pectin and hemicellulose) via hydrogen bonding and hydrophobic interactions. Transmembrane transport involves passive diffusion, anion channels, aquaporins, and potentially carrier-mediated processes. At the subcellular level, PFAS primarily accumulate in the cell wall and plasma membrane, with a fraction sequestered into vacuoles, chloroplasts, and mitochondria. This compartmentalization triggers a cascade of phytotoxic effects, including reactive oxygen species burst, lipid peroxidation, membrane disruption, photosynthetic inhibition, and hormonal imbalance. Plants deploy detoxification strategies such as vacuolar sequestration and activation of enzymatic and non-enzymatic antioxidant systems, exhibiting hormetic dose-response. Advanced omics and imaging techniques have elucidated the molecular and spatial landscape of PFAS-plant interactions. This integrative framework enhances our mechanistic understanding of PFAS phytotoxicity, supporting ecological risk assessment and phytoremediation strategies.